Body Organization and Integumentary System LECTURE PACKET 7 READING: CHAPTER 4 COPYRIGHT 2008 PEARSON EDUCATION

Outline ▪ Tissues ▪ Cell to cell contact ▪ Body cavities ▪ Membranes ▪ Homeostasis ▪ Integumentary system (skin, hair, and nails) COPYRIGHT 2008 PEARSON EDUCATION

Tissues ▪ A tissue is a group of cells of similar type that work together to serve a common function. ▪ There are four primary tissue types: - Epithelial tissue - Connective tissue - Muscle tissue - Nervous tissue COPYRIGHT 2008 PEARSON EDUCATION

Tissues ▪ Epithelial tissue covers body surfaces, lines body cavities and organs, and forms glands. ▪ Connective tissue serves as a storage site for fat, plays an important role in immunity and provides the body and its organs with protection and support. COPYRIGHT 2008 PEARSON EDUCATION

Tissues ▪ Muscle tissue is responsible for body movement and for movement of substances through the body. ▪ Nervous tissue conducts nerve impulses from one part of the body to another. COPYRIGHT 2008 PEARSON EDUCATION

Epithelial Tissue ▪ All have a free surface and a basement. ▪ Free surface - May be specialized for protection, secretion, or absorption. ▪ Basement membrane - Noncellular layer that binds the epithelial cells to underlying connective tissue and helps the epithelial tissue resist stretching. COPYRIGHT 2008 PEARSON EDUCATION

Epithelial Tissue ▪ There are three types of epithelial tissue. ▪ Squamous is made up of flattened, or scale-like, cells. - Flattened shape allows oxygen and carbon dioxide to diffuse across the lining. ▪ Cuboidal is made up of cube-shaped cells. - Mostly specialized for secretion and absorption. ▪ Columnar consists of elongated, column-shaped cells. - Mostly specialized for absorption and secretion. COPYRIGHT 2008 PEARSON EDUCATION

Epithelial Tissue: gland ▪ A gland is epithelial tissue that secretes a product. ▪ Exocrine glands secrete their products into ducts leading to body surfaces, cavities, or organs. ▪ Endocrine glands lack ducts and secrete their products, hormones, into spaces just outside the cells. COPYRIGHT 2008 PEARSON EDUCATION

Connective Tissue ▪ Its main role is to bind and provide support, but it can also transport and store energy. ▪ All connective tissues contain cells embedded in an extracellular matrix. - Matrix consists of protein fibers and a “ground substance,” which can be solid (bone), fluid (blood), or gelatinous (cartilage). COPYRIGHT 2008 PEARSON EDUCATION

Connective Tissue: Matrix Proteins ▪ Collagen fibers are strong and ropelike and can withstand pulling because of their great tensile strength. ▪ Elastic fibers contain random coils and can stretch and recoil like a spring. ▪ Reticular fibers are thin strands of collage that branch extensively, forming interconnecting networks suitable for supporting soft tissues (like liver and spleen). COPYRIGHT 2008 PEARSON EDUCATION

Connective Tissue Types: Connective Tissue Proper ▪ Connective tissue proper. - Can be dense or loose, depending on the ratio of cells to extracellular fibers. - Adipose tissue is an example of loose connective tissue. - Energy store as fat - Provides insulation - Shock absorber - Dense connective tissue is found in ligaments (structures that join bone to bone), tendons (muscle to bone), and the dermis (layer of skin below the epidermis) COPYRIGHT 2008 PEARSON EDUCATION

Connective Tissue Types: Specialized Connective Tissue ▪ Specialized connective tissue comes in three types: cartilage, bone, and blood. ▪ Cartilage is tough but flexible. - Serves as a cushion between certain bones - Helps maintain structure of certain body parts (i.e. ears and nose) - Gelatinous ground substance. COPYRIGHT 2008 PEARSON EDUCATION

Connective Tissue Types: Specialized Connective Tissue ▪ Specialized connective tissue comes in three types: cartilage, bone, and blood. ▪ Bone, in combination with cartilage, and other components of joints, make up the skeletal system. - Protection - Support for internal structure - Movement, in conjunction with muscles - Storage of lipids, calcium, and phosphorus - Production of blood cells - Matrix is hardened by calcium COPYRIGHT 2008 PEARSON EDUCATION

Connective Tissue Types: Specialized Connective Tissue ▪ Specialized connective tissue comes in three types: cartilage, bone, and blood. ▪ Blood has a liquid matrix called plasma in which blood cells and platelets are suspended in. - Transport various substances COPYRIGHT 2008 PEARSON EDUCATION

Muscle Tissue ▪ There are three types of muscle tissues: - Skeletal - Cardiac - Smooth COPYRIGHT 2008 PEARSON EDUCATION

Muscle Tissue: Skeletal ▪ Skeletal muscle is usually attached to bones. ▪ When skeletal muscle tissue contracts, it usually moves a part of the body. ▪ It is under voluntary control. COPYRIGHT 2008 PEARSON EDUCATION

Muscle Tissue: Cardiac ▪ Cardiac muscle tissue is found only in the walls of the heart, where its contractions are responsible for pumping blood to the rest of the body. ▪ Contraction is involuntary. COPYRIGHT 2008 PEARSON EDUCATION

Muscle Tissue: Cardiac ▪ Smooth muscle tissue is found in the walls of blood vessels and airways, where its contraction reduces the flow of blood or air. ▪ Contraction is involuntary. COPYRIGHT 2008 PEARSON EDUCATION

Cell adhesion ▪ The cells that make up tissues are held together by three types of junctions. - Tight junctions - Adhesion junctions - Gap junctions COPYRIGHT 2008 PEARSON EDUCATION

Cell adhesion: tight junctions ▪ Tight junctions prevent substances from leaking across tissues and they hold cells together. They are found between epithelial cells of the digestive tract, where they prevent digestive enzymes and microorganisms from entering the blood. COPYRIGHT 2008 PEARSON EDUCATION

Cell adhesion: adhesion junctions ▪ Adhesion junctions hold adjacent cells together and allow tissues to be flexible. ▪ Found in tissues that are often stretched, such as the skin and opening of the uterus. COPYRIGHT 2008 PEARSON EDUCATION

Cell adhesion: gap junctions ▪ Gap junctions are open channels between cells, allowing rapid communication due to quick transfer of ions and small molecules between neighboring cells. ▪ They are found mostly in the heart and smooth muscle. COPYRIGHT 2008 PEARSON EDUCATION

Which junction allows for rapid communication between neighboring cells? 1.Tight 2.Gap 3.Adhering COPYRIGHT 2008 PEARSON EDUCATION

Which junction prevents substances from leaking across tissues? 1.Tight 2.Gap 3.Adhering COPYRIGHT 2008 PEARSON EDUCATION

Body Cavities COPYRIGHT 2008 PEARSON EDUCATION ▪ We have two main body cavities: - Dorsal (posterior) - Ventral (anterior)

Body Cavities: Ventral Cavity COPYRIGHT 2008 PEARSON EDUCATION ▪ Thoracic cavity divides into: - Pleural cavity - Pericardial cavity ▪ The abdominal cavity contains the digestive system, the urinary system, and the reproductive system.

Body Cavities: Dorsal Cavity COPYRIGHT 2008 PEARSON EDUCATION ▪ Dorsal cavity is divided into two cavities: - Cranial (contains brain) - Spinal (contains spinal cord)

The arrow is pointing to which cavity? 1.Cranial 2.Thoracic 3.Abdominal COPYRIGHT 2008 PEARSON EDUCATION

The arrow is pointing to which cavity? 1.Cranial 2.Thoracic 3.Abdominal COPYRIGHT 2008 PEARSON EDUCATION

The arrow is pointing to which cavity? 1.Cranial 2.Thoracic 3.Abdominal COPYRIGHT 2008 PEARSON EDUCATION

Body Cavities: Dorsal Cavity COPYRIGHT 2008 PEARSON EDUCATION ▪ Dorsal cavity is divided into two cavities: - Cranial (contains brain) - Spinal (contains spinal cord)

Membranes COPYRIGHT 2008 PEARSON EDUCATION ▪ Body cavities and organ surfaces are covered with membranes—sheets of epithelium supported by connective tissue. ▪ There are four types of membranes: 1.Mucous 2.Serous 3.Synovial 4.Cutaneous

Membranes: Mucous COPYRIGHT 2008 PEARSON EDUCATION ▪ Mucous membranes line passages to the exterior world, including those of the respiratory, digestive, reproductive, and urinary systems in the body. ▪ They secrete mucus.

Membranes: Serous COPYRIGHT 2008 PEARSON EDUCATION ▪ Serous membranes line thoracic and abdominopelvic cavities and the organs contained in them. ▪ They secrete lubricating fluid.

Membranes: Synovial COPYRIGHT 2008 PEARSON EDUCATION ▪ Synovial membranes line cavities of freely movable joints (i.e. knee). ▪ They secrete a lubricating fluid.

Membranes: Cutaneous COPYRIGHT 2008 PEARSON EDUCATION ▪ Cutaneous membranes, or skin, covers the outside of the body. - It is thick, waterproof, and relatively dry.

Homeostasis COPYRIGHT 2008 PEARSON EDUCATION ▪ Homeostasis is the ability to maintain the body at a relatively stable internal environment despite changes in external environment. ▪ The body uses the nervous system and the endocrine system to maintain homeostasis. ▪ Homeostasis is controlled mostly by negative feedback mechanism.

Homeostasis COPYRIGHT 2008 PEARSON EDUCATION

Negative Feedback Mechanism COPYRIGHT 2008 PEARSON EDUCATION ▪ A receptor (sensor) detects a change in some factor or event (variable) in the internal or external environment. ▪ It relays this information to the control center, where the information is integrated and an appropriate response is subsequently sent out. ▪ The effector carries out the response by returning the variable to its original set point.

Negative Feedback Example COPYRIGHT 2008 PEARSON EDUCATION ▪ Example: Calcium regulation ▪ Calcium is stored in the bones and circulates in the blood stream. ▪ Cells in the bones called osteoclasts release calcium from bone.

Negative Feedback Example COPYRIGHT 2008 PEARSON EDUCATION ▪ Stimulus: When calcium levels drop too low in the blood stream, this triggers a response from the sensor. ▪ Sensor: Parathyroid glands ▪ Control Center: It instructs parathyroid gland to release more parathyroid hormone. ▪ Effectors: Osteoclast cells in the bone release calcium. Kidneys also reabsorb more calcium.

Negative Feedback Example COPYRIGHT 2008 PEARSON EDUCATION ▪ Stimulus: When calcium levels increase in the blood stream, this triggers a response from the sensor. ▪ Sensor: Parathyroid glands ▪ Control Center: It instructs parathyroid gland to release less parathyroid hormone. ▪ Effectors: Osteoclast cells in the bone releases less calcium. Kidneys also reabsorbs less more calcium.

Positive Feedback COPYRIGHT 2008 PEARSON EDUCATION ▪ You also have positive feedback system in your body. ▪ A positive feedback is when a change in a variable would stimulate the control center to increase the magnitude of this change in the same direction. ▪ An example would be blood clotting. Activated platelets release a signal that would activate more platelets.

Hormones COPYRIGHT 2008 PEARSON EDUCATION ▪ Hormones are substances released into the blood and produce an affect in another part of the body.

Organs COPYRIGHT 2008 PEARSON EDUCATION ▪ An organ is a group of tissues that work together to perform a specific function. ▪ In turn, organs work together to form an organ system.

Integumentary System COPYRIGHT 2008 PEARSON EDUCATION ▪ Components of the integumentary system: - Skin - Nails - Hair - Exocrine glands (sweat and oil glands)

Integumentary System: Functions COPYRIGHT 2008 PEARSON EDUCATION 1.Provides a barrier for protection against bacteria, UV radiation, chemicals, and physical injury 2.Reduce water loss (water-resistant protein keratin) 3.Temperature regulation 4.Vitamin D production (UV radiation converts modified cholesterol) 5.Contains receptors that detect pain, temperature, and pressure

Integumentary System: Skin Layers COPYRIGHT 2008 PEARSON EDUCATION ▪ The skin has two layers: - Epidermis: thin outer layer of stratified squamous epithelial tissue - Dermis: thick underlying layer of mainly connective tissue

Integumentary System: Skin Layers COPYRIGHT 2008 PEARSON EDUCATION

Skin Layers: Epidermis COPYRIGHT 2008 PEARSON EDUCATION ▪ The epidermis consists of several layers of squamous epithelial cells (stratified). - Deepest layer contains rapidly dividing cells - Outer surface is made up of dead skin cells - Protective properties come from keratin (protection against excessive water loss) - Melanocytes produce melanin, which contributes to skin color and UV protection.

Skin Layers: Dermis COPYRIGHT 2008 PEARSON EDUCATION ▪ The dermis primarily consists of connective tissue. ▪ It also contains vascular tissue, hair follicles, sweat glands, nerves, and sensory receptors. ▪ Collage and elastic fibers are found in the lower layer, which allow the skin to stretch and return to its original shape.

Hypodermis COPYRIGHT 2008 PEARSON EDUCATION ▪ The hypodermis is a layer of loose connective tissue beneath the dermis and epidermis connecting the dermis to other tissues. ▪ The hypodermis is not a part of the skin. It lays underneath the skin.

Integumentary System: Accessory Organs COPYRIGHT 2008 PEARSON EDUCATION ▪ Nails protect the sensitive tips of fingers and toes. They are modified skin tissue hardened by the protein keratin. ▪ Hair serves as protection. Hair follicles are found in the dermis, where sebum is released to lubricate the hair. ▪ Three types of glands (oil, sweat, and wax) develop from epidermal cells.

Integumentary System: Accessory Organs COPYRIGHT 2008 PEARSON EDUCATION ▪ Three types of glands (oil, sweat, and wax) develop from epidermal cells. ▪ Oil glands secrete sebum, an oily substance made of fats, cholesterol, proteins, and salts. - This lubricates skin and hair and contains substances that inhibit growth of certain bacteria.

Integumentary System: Accessory Organs COPYRIGHT 2008 PEARSON EDUCATION ▪ Three types of glands (oil, sweat, and wax) develop from epidermal cells. ▪ Sweat glands and sebaceous glands produce sweat, which is largely water plus some salts, lactic acid, vitamin C, and metabolic wastes such as urea. - Principal function is to help regulate body temperature by evaporating from the skin surface.

Skin Cancer COPYRIGHT 2008 PEARSON EDUCATION ▪ UV radiation causes more melanin to be produced. Melanin absorbs UV radiation before it can damage the genetic information of deeper layers of skin. ▪ This protection eventually becomes overcome with chronic, lengthy exposure to UV radiation.

Skin Cancer COPYRIGHT 2008 PEARSON EDUCATION ▪ Three types of skin cancer: 1. Basal cell carcinoma: Arises from the rapidly dividing cells of the deepest layer of the epidermis. 2. Squamous cell carcinoma: Arises in the newly formed skin cells as they flatten and move toward the skin surface. 3. Melanoma: Least common and most dangerous. Arises from melanocytes. It can spread rapidly and infiltrate the vital organs.

Skin Cancer COPYRIGHT 2008 PEARSON EDUCATION ▪ ABCDE! -Assymetry -Border is unclear -Color is not consistent -Diameter is > 5 mm -Evolving, changing in size and color